Numerous time zones segment the world, with each time zone being a region that observes its own uniform standard time for legal, commercial, and social purposes. A clock must be set to correspond to the time zone in which it resides to show correct time for that time zone, especially if the clock is required to update itself for daylight saving time at the correct date and time applicable in the region.
Mobile devices typically include electronic clocks. Many mobile devices do not have the ability to automatically determine the time zone in which the mobile devices are located. Some mobile devices attempt to determine their time zone using Network Identity & Time Zone (NITZ) data, which can be unreliable or unavailable in many locations around the world.